An example of a magnetic head for recording and reproduction is a magnetic head in which an electromagnetic conversion element is mounted on a slider that flies above and moves relative to a recording medium. Such a magnetic head can be produced by a method as follows. First, an insulating film composed of amorphous alumina is formed on a ceramic substrate composed of an Al2O3—TiC ceramic, and a plurality of electromagnetic conversion elements are then formed on the insulating film.
Subsequently, the ceramic substrate having the electromagnetic conversion elements thereon is cut into strips, and a cut surface is polished to form a mirror-finished surface. A part of the mirror-finished surface is then removed by an ion-milling method or a reactive ion etching method to form a flow path surface. Subsequently, the strip-shaped ceramic substrate is divided into chips, thus obtaining a magnetic head in which an electromagnetic conversion element is mounted on a slider.
For a recording medium drive device, such as a hard disk drive, in which such a magnetic head is installed, an increase in a storage capacity has been increasingly desired and a higher recording density has been required. To meet these requirements, it is required to markedly reduce a flying height (flying amount) of the magnetic head from a magnetic disk serving as a recording medium to 10 nm or less. In a case of such a small flying height (flying amount), the magnetic head produced as described above may contact the recording medium. Accordingly, it is desired that crystal grains of a composition of a slider constituting the magnetic head be not readily detached by the impact of this contact.
In the Al2O3—TiC material of the magnetic head slider, it may be difficult to reduce the grain growth of Al2O3 crystal grains. In such a case, abnormal grain growth of Al2O3 crystal grains may occur during sintering. As a result, detachment of the Al2O3 crystal grains may readily occur during a process of cutting a substrate for a magnetic head into strips and forming a flow path surface.
Accordingly, it is desired to reduce detachment of crystal grains during processing (such as cutting, trimming, and etching) of a substrate for a magnetic head and detachment of crystal grains from a slider with a magnetic head made from the substrate.